Wii Controls
I found this bit of information regarding the gameplay on the Wii Controller.
Similar to playing NES games on the Virtual Console, the Wii Remote is held sideways, where the player moves using the control pad and jumps using the 2 button. Pressing the A Button (if the player’s character is Mario) switches the viewpoint from 2D to 3D, or in other words, from a side-scroller to a third-dimensional landscape. This allows a more thorough sense of depth and more action taking place. However, this perspective is only temporary: when the player switches to 3D mode, a 10-second timer appears beneath the player’s HP, as a row of rainbow-colored squares. When it reaches zero the perspective snaps back to 2D, and then slowly recovers.
It has been stated by Nintendo Power that as the player progresses he will pick up new allies called Pixls, which give the player new ways to use the Wii Remote in game. For example, one Pixl, named Tippy, allows the player to use the remote as a pointer, using it to find hidden objects and learn about enemies.